A study investigates the practice of discarding unimportant features based on small aggregate SHAP values.
The study finds that small aggregate SHAP values do not necessarily imply that the corresponding feature has no effect on the function.
To address this issue, the study suggests aggregating SHAP values over the extended support, which is the product of the marginals of the underlying distribution.
The study also extends the findings to KernelSHAP, demonstrating that a small aggregate value justifies feature removal, regardless of the accuracy of the KernelSHAP approximation.